Benfotiamine (rINN, or S-benzoylthiamine O-monophoshate) is a synthetic S-acyl derivative of thiamine (vitamine B1). After absorption, benfotiamine can be dephosphorylated by cells bearing an ecto-alkaline phosphatase to the lipid-soluble S-benzoylthiamine. Benfotiamine should not be confused with allithiamine, a naturally occurring thiamine disulfide derivative with a distinct pharmacological profile.